Geology of Indiana, ^c. 133 



fine chalcedony, and sometimes the interior was the same sub- 

 stance, in the form of balls ; all these were sometimes com- 

 bined, forming agates of great beauty. 



Carbonate of lime, crystallized, is sometimes found ; and 

 many of the caves afford line stalactites. 



There is a large caye near Corydon, celebrated for the pro- 

 duction of sulphate of magnesia, or Epsom salts. It has been 

 explored for the distance of several miles. When it was first 

 discovered, the bottom, in many places, was covered to the 

 depth of several inches, with pure, brilliant, needle-shaped 

 crystals of sulphate of magnesia. By some mysterious process 

 of nature, or rather of Divine benevolence, the production of 

 this useful salt is continually going on. This cave also produ- 

 ces some other salts in small quantities : nitrate of lime, nitrate 

 of magnesia, sulphate of hme, &c. 



Where the basis of the country is limestone, the waters 

 always take up a great quantity of lime, and some of them posr 

 sess great petrifying powers. I saw many specimens of petri- 

 factions : a tuft of moss, the form perfectly preserved ; leaves, 

 bark, and branches of tress ; insects, and many others. 



Many of the springs are strongly impregnated with sulphur, 

 and some of them are saturated with sulphuretted hydrogen. 

 I found the opinion universally prevalent among the people of 

 this state, that the first appearance of these sulphur springs 

 was immediately subsequent to the earthquakes of 1812. They 

 say, that then new springs, impregnated with sulphur, broke 

 out, and the waters of some old springs, for the first time, gave 

 indications of this mineral. A sensible farmer, Vi'ho has a large 

 sulphur-fountain, boiling up from the bottom of a river near 

 its bank, assured me, that there was no trace of this spring 

 until after the period to which I have alluded. He could 

 have no interest in deceiving me ; and if he diddeceive me, 

 his conduct could originate only in that love of the marvellous 

 which is so characteristic of the human mind. He moreover 

 assured me that the " water had been growing weaker, (t© 

 use his phrase) ever since its first appearance." I have room 

 only to mention, among the minerals of Indiana, many varieties 

 of clay, ochres, gypsum, alabaster, muriat of soda, (very com- 

 mon,) iron ore, and antimony. 



